1. Field of the Invention
The present invention relates to a retracting mechanism of a vehicular outer mirror device disposed in a vehicle.
2. Description of the Related Art
There is a vehicular door mirror device disposed with a retracting mechanism (e.g., see Japanese Patent Application Publication (JP-A) No. 2002-67805).
This type of retracting mechanism includes a support shaft fixed to a vehicle body, and a case member is pivotably supported on the support shaft. A rearview mirror is coupled to the case member, and the case member is always pivoted integrally with the mirror.
A gear plate formed as a helical gear is disposed on the support shaft inside the case member in a state where the rotation of the gear plate is prevented (deterred). A motor is fixed inside the case member, and a motor gear such as a worm gear is coupled to the output shaft of the motor. Intermediate gears such as twin gear comprising a worm gear and a helical gear are disposed inside the case member. The gears mesh with the motor gear of the motor output shaft and the gear plate, so that the motor gear and the gear plate are coupled together. Thus, when the motor is driven, the intermediate gears rotate while meshing the periphery of the gear plate. Thus, the case member is pivoted around the support shaft, and the mirror is stored or erected.
At the coupled portion of the output shaft of the motor and the motor gear, the end portion of the motor output shaft is formed in a double D-cut, where two sites opposing each other in the circumferential direction are chamfered in planar shapes, in order to transmit the rotational force of the motor to the motor gear. Thus, the output shaft of the motor and the motor gear are coupled together, and the rotational force of the motor is transmitted to the motor gear (e.g., see Japanese Utility Model Application Publication No. 5-58484).
However, when the motor is driven, a reaction force from the gear plate and the intermediate gears acts on the motor gear, and the motor gear tries to slant. Namely, at the coupled portion of the output shaft of the motor and the motor gear, a reaction force alternately acts on the D-cut surface and the circumferential surface other than the D-cut portion, and the motor gear repeatedly slants (wobbles) and does not slant (does not wobble) at a 90° pitch in accompaniment with the rotation of the output shaft of the motor. As a result, abnormal noises occur.